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Abstract:

A wireless headset capable of receiving audio signals transmitted
wirelessly and compatible for use in an MRI scanner is disclosed. The
headset includes a first wireless module connected to the first earphone
and a second wireless module connected to the second earphone. Each
wireless module is electrically connected to a speaker in the respective
earphone. The first wireless module receives the audio signal from a
remote source and coordinates transmission of the audio signal to each of
the speakers. The compact nature of each earphone minimizes the length of
wire runs. In addition, the headset is made of materials having low
magnetic susceptibility such that they will not be affected by the
magnetic field from the MRI scanner.

Claims:

1. A headset for a patient to wirelessly receive an audio signal during a
magnetic resonance image (MRI) scan, the headset comprising: a first
earphone, including: a first wireless audio module configured to receive
the audio signal and to wirelessly retransmit at least a portion of the
audio signal, and a first speaker electrically connected to the first
wireless audio module and configured to reproduce at least a portion of
the audio signal; a second earphone, including: a second wireless audio
module configured to receive the portion of the audio signal
retransmitted from the first wireless audio module, and a second speaker
electrically connected to the second wireless audio module and configured
to reproduce the portion of the audio signal received by the second
wireless audio module; and a headband having a first end and a second
end, wherein the first earphone is connected proximate to the first end
and the second earphone is connected proximate to the second end.

2. The headset of claim 1 wherein each of the components of the headset
is made of materials having a low magnetic signature.

3. The headset of claim 2 wherein each of the components of the headset
is made of materials having a low magnetic susceptibility.

4. The headset of claim 1 wherein: the first earphone further includes a
first proximity sensor having a detection range and configured to
generate a signal corresponding to the presence of an object within the
detection range; the second earphone further includes a second proximity
sensor having a detection range and configured to generate a signal
corresponding to the presence of an object within the detection range;
and each of the first and second wireless audio modules are configurable
to operate in a first operating mode or a second operating mode as a
function of the signal generated by the first and the second proximity
sensors, respectively.

5. The headset of claim 1 wherein: the audio signal is a stereo signal,
the first wireless audio module transfers a first channel of the audio
signal to the first speaker, the first wireless audio module wirelessly
retransmits a second channel of the audio signal to the second wireless
audio module, and the second wireless audio module transfers the second
channel of the audio signal to the second speaker.

6. The headset of claim 1 wherein: the first earphone further includes a
first microphone configured to detect audio signals proximate to the
first earphone and generate a first signal corresponding to the audio
signals proximate to the first earphone; the first wireless audio module
is further configured to: receive the first signal corresponding to the
audio signals proximate to the first earphone, generate a first audio
signal that cancels at least a portion of the audio signals proximate to
the first earphone, and transfer the first audio signal that cancels at
least a portion of the audio signals to the first speaker; the second
earphone further includes a second microphone configured to detect audio
signals proximate to the second earphone and generate a second signal
corresponding to the audio signals proximate to the second earphone; and
the second wireless audio module is further configured to receive the
second signal corresponding to the audio signals proximate to the second
earphone, generate a second audio signal that cancels at least a portion
of the ambient audio signals proximate to the second earphone, and
transfer the second audio signal that cancels at least a portion of the
ambient audio signals to the second speaker.

7. The headset of claim 6 further comprising a third microphone mounted
to one of the first and second earphones, wherein the third microphone is
configured to receive the patient's voice and transfer a signal to one of
the first or second wireless audio modules and wherein the first or
second wireless audio module is configured to wirelessly transmit the
signal received from the microphone.

8. The headset of claim 7 wherein the first or second wireless audio
module is further configured to add the respective first or second signal
that cancels at least a portion of the ambient audio signals to the
signal received from the microphone prior to wirelessly transmitting the
signal.

9. The headset of claim 1 further comprising: a support arm, having a
first end and a second end, the first end of the support arm connected to
one of the first end or the second end of the headband; and a microphone
mounted proximate the second end of the support arm, wherein the
microphone is configured to receive the patient's voice and transfer a
signal to one of the first or second wireless audio modules and wherein
the first or second wireless audio module is configured to wirelessly
transmit the signal received from the microphone.

10. The headset of claim 9 wherein the microphone receives ambient noise
along with the patient's voice and the first or second wireless audio
module is configured to: process the signal to separate the patient's
voice from the ambient noise, generate an audio signal that cancels at
least a portion of the ambient audio signals, and add the audio signal
that cancels at least a portion of the ambient audio signals to the
signal received from the microphone prior to wirelessly transmitting the
signal.

11. The headset of claim 1 wherein: the first earphone further includes a
first cushion removably mounted to the first earphone and configured to
be positioned between the first earphone and the patient; and the second
earphone further includes a second cushion removably mounted to the
second earphone and configured to be positioned between the second
earphone and the patient.

12. The headset of claim 1 wherein each of the first and the second
earphone is a bud-style earphone, configured to engage a patient's ear
canal.

13. The headset of claim 1 wherein at least one of the first and second
earphones further includes a display unit.

14. An MRI compatible headset for receiving a wireless audio signal,
comprising: a first earphone, including: a wireless audio module
configured to receive the wireless audio signal and output a wired audio
signal, a signal processing device configured to receive the wired audio
signal and to process the wired audio signal into a first channel signal
and a second channel signal, and a first speaker configured to receive
the first channel signal and reproduce the first channel signal as an
audio output; a second earphone including a second speaker configured to
receive the second channel signal and reproduce the second channel signal
as an audio output; and a transmission means for transmitting the second
channel signal between the signal processing device and the second
speaker, wherein each of the components of the headset are made of
materials having a low magnetic signature.

15. The MRI compatible headset of claim 14 wherein each of the components
of the headset is made of materials having a low magnetic susceptibility.

16. The MRI compatible headset of claim 14 wherein the transmission means
includes an electrical conductor connected between the first and second
earphones and at least one cable trap connected in series with the
electrical conductor, the cable trap configured to reduce currents
induced by magnetic fields during an MRI scan.

17. The MRI compatible headset of claim 14 wherein the transmission means
includes a first optical transceiver in the first earphone, a second
optical transceiver in the second earphone, and an optical fiber
connecting the first and second optical transceivers.

18. The MRI compatible headset of claim 14 wherein the transmission means
includes a second wireless audio module in the second earphone and the
wireless audio module in the first earphone is configured to retransmit
the second channel signal to the second wireless audio module.

19. The MRI compatible headset of claim 14 wherein: the first earphone
further includes a proximity sensor having a detection range and
configured to generate a signal corresponding to the presence of an
object within the detection range; and the wireless audio module and the
signal processing device are configurable to operate in a first operating
mode or a second operating mode as a function of the signal generated by
the proximity sensor.

20. The MRI compatible headset of claim 14 wherein the wireless audio
signal is a stereo signal having a left and a right channel and the
signal processing device separates the left channel into one of the first
or second channel signals and separates the right channel into the other
of the first or second channel signals.

21. The MRI compatible headset of claim 14 wherein: the first earphone
further includes at least one microphone configured to detect ambient
audio signals and generate a signal corresponding to the ambient audio
signals; the wireless audio module is further configured to: receive the
signal corresponding to the ambient audio signals, and generate an audio
signal that cancels at least a portion of the ambient audio signals; and
the signal processing device is further configured to combine the audio
signal that cancels at least a portion of the ambient audio signals with
at least one of the first channel signal and the second channel signal.

22. The MRI compatible headset of claim 21 further comprising a
microphone configured to receive the, patient's voice and transfer a
signal to the wireless audio module corresponding to the patient's voice,
wherein the wireless audio module is further configured to add the audio
signal that cancels at least a portion of the ambient audio signals to
the signal received from the microphone and wirelessly transmitting the
resulting signal.

23. The MRI compatible headset of claim 14 wherein each of the first and
the second earphone is a bud-style earphone, configured to engage a
patient's ear canal.

24. The MRI compatible headset of claim 14 further comprising: a support
arm having a first end and a second end, the first end of the support arm
connected to one of the first earphone or the second earphone; and a
microphone mounted proximate the second end of the support arm, wherein
the microphone is configured to receive the patient's voice and transfer
a signal to the wireless audio module and wherein the wireless audio
module is configured to wirelessly transmit the signal received from the
microphone.

25. The MRI compatible headset, of claim 24 wherein the microphone
receives ambient noise along with the patient's voice and the wireless
audio module is configured to: process the signal to separate the
patient's voice from the ambient noise; generate an audio signal that
cancels at least a portion of the ambient audio signals, and add the
audio signal that cancels at least a portion of the ambient audio signals
to the signal received from the microphone prior to wirelessly
transmitting the signal.

26. The MRI compatible headset of claim 14 wherein at least one of the
first and second earphones further includes a display unit.

27. A headset for a patient to wirelessly receive an audio signal during
a magnetic resonance image (MRI) scan, the headset comprising: a first
earphone, including: a first wireless audio module configured to receive
the audio signal and to wirelessly retransmit at least a portion of the
audio signal, and a first speaker electrically connected to the first
wireless audio module and configured to reproduce at least a portion of
the audio signal; a second earphone, including: a second wireless audio
module configured to receive the portion of the audio signal
retransmitted from the first wireless audio module, and a second speaker
electrically connected to the second wireless audio module and configured
to reproduce the portion of the audio signal received by the second
wireless audio module, wherein each of the components of the headset is
made of materials having a low magnetic signature and a low magnetic
susceptibility.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. provisional application
Ser. No. 61/648,876, filed May 18, 2012, the entire contents of which is
incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The subject matter disclosed herein relates to magnetic resonance
imaging (MRI) compatible headphones. More specifically, headphones
suitable for use by a patient in an MRI scanner are disclosed.

[0003] As is, known to those skilled in the art, an MRI system alternately
generates a strong magnetic field and then detects the faint nuclear
magnetic resonance (NMR) signals given off by nuclei in the presence of
the magnetic field. The NMR signals are received by antennas, also known
as coils, and transmitted to the MRI scanner for reconstruction into an
MRI image. In order to provide a clear image, it is desirable to minimize
electromagnetic interference from outside sources.

[0004] As a result, MRI scanners are located within a shielded room 2,
also known as the scan room (see FIG. 9). The scan room 2 includes walls,
or panels, which typically incorporate RF shielding within the wall. The
controller 5 for the MRI scanner 1 is typically located in an adjacent
control room 3. A window 4 permits an operator to observe activity within
the scan room 2 from the adjacent control room 3. The operator often
needs to communicate with the patient, for example, to provide
instructions to the patient during the scan. Consequently, a microphone
may be provided in the control room for the, operator and a headset
provided to the patient to receive instructions from the MRI operator.

[0005] However, the MRI environment creates numerous challenges that make
conventional electronic headsets unusable in the MRI environment. Most
commercial headsets utilize a magnetic speaker driver and may include one
or more other components that are susceptible to magnetic fields. The
magnetic field generated by the MRI scanner may, at a minimum, interfere
with these devices, and at worst, pull the devices into the bore of the
scanner, potentially injuring the patient. Further, non-magnetic metal
components may be susceptible to radio frequency (RF) induced heating.
Also, long wire runs, for example, between the control room and the
patient or even between earphones function as antennas. These long wire
runs raise the potential of both radiating electromagnetic interference
detectable by the MRI scanner due to audio signals transmitted on the
wire and receiving interference from the MRI scanner which degrades the
audio signal provided to the patient.

[0006] Historically, these limitations of conventional electronic headsets
have been overcome by providing pneumatic headsets to the patient.
However, such a system is not without drawbacks. The pneumatic headsets
require a dedicated controller to convert an electronic audio signal to a
pneumatic audio signal for transmission to the patient. Pneumatic tubing
extending from this controller to the patient is also required.

BRIEF DESCRIPTION OF THE INVENTION

[0007] The subject matter disclosed herein describes a wireless headset
capable of receiving audio signals transmitted wirelessly and compatible
for use in an MRI scanner. The headset includes a first wireless module
connected to the first earphone and a second wireless module connected to
the second earphone. Each wireless module is electrically connected to a
speaker in the respective earphone. The first wireless module receives an
audio signal from a remote source and coordinates transmission of the
audio signal to each, of the speakers. The compact nature of each
earphone minimizes the length of wire runs. Further, wireless
communications between earphones eliminates a wire extending between the
earphones. In addition, the headset is made of materials having low
magnetic susceptibility such that they will not be affected by the
magnetic field from the MRI scanner.

[0008] According to a first embodiment of the invention, a headset for a
patient to wirelessly receive an audio signal during a magnetic resonance
image (MRI) scan includes a first earphone, a second earphone, and a
headband having a first end and a second end. The first earphone is
connected proximate to the first end and the second earphone is connected
proximate to the second end. The first earphone includes a first wireless
audio module configured to receive the audio signal and to wirelessly
retransmit at least a portion of the audio signal and a first speaker
electrically connected to the, first wireless audio module and configured
to reproduce at least a portion of the audio signal. The second earphone
includes a second wireless audio module configured to receive the portion
of the audio signal retransmitted from the first wireless audio module
and a second speaker electrically connected to the second wireless audio
module and configured to reproduce the portion of the audio signal
received by the second wireless audio module. Each of the components of
the headset is made of materials having low magnetic susceptibility.

[0009] According to another aspect of the invention, the first earphone
may further include a first proximity sensor having a detection range and
the second earphone may further include a second proximity sensor having
a detection range. Each proximity sensor is configured to generate a
signal corresponding to the presence of an object within the detection
range. Each of the first and second wireless audio modules are
configurable to operate in a first operating mode or a second operating
mode as a function of the signal generated by the first and the second
proximity sensors, respectively. The audio signal may be a stereo signal.
The first wireless audio module transfers a first channel of the audio
signal to the first speaker, and the first wireless audio module
wirelessly retransmits a second channel of the audio signal to the second
wireless audio module. The second wireless audio module transfers the
second channel of the audio signal to the second speaker.

[0010] According to yet another aspect of the invention, the first
earphone may further include at least one first microphone configured to
detect audio signals proximate to the first earphone and generate a first
signal corresponding to the audio signals proximate to the first
earphone. The first wireless audio module is further configured to
receive the first signal corresponding to the audio signals proximate to
the first earphone, generate a first audio signal that cancels at least a
portion of the audio signals proximate to the first earphone, and
transfer the first audio signal that cancels at least a portion of the
audio signals to the first speaker. The second earphone may further
include at least one second microphone configured to detect audio signals
proximate to the second earphone and generate a second signal
corresponding to the audio signals proximate to the second earphone. The
second wireless audio module is further configured to receive the second
signal corresponding to the audio signals proximate to the second
earphone, generate a second audio signal that cancels at least a portion
of the ambient audio signals proximate to the second earphone, and
transfer the second audio signal that cancels at least a portion of the
ambient audio signals to the second speaker.

[0011] According to still another aspect of the invention, the headset may
include a support arm having a first end and a second end. The first end
of the support arm is connected to one of the first end or the second end
of the headband, and a microphone is mounted proximate the second end of
the support arm. The microphone is configured to receive the patient's
voice and transfer a signal to either the first or second wireless audio
modules. The first or second wireless audio module is configured to
wirelessly transmit the signal received from the microphone. The
microphone also receives ambient noise along with the patient's voice.
The first or second wireless audio module is configured to process the
signal to separate the patient's voice from the ambient noise, generate
an audio signal that cancels at least a portion of the ambient audio
signals, and add the audio signal that cancels at least a portion of the
ambient audio signals to the signal received from the microphone prior to
wirelessly transmitting the signal.

[0012] According to another embodiment of the invention, an MRI compatible
headset for receiving a wireless audio signal includes a first earphone
and a second earphone. The first earphone includes a wireless audio
module, a signal processing device, and a first speaker. The wireless
audio module is configured to receive the wireless audio signal and
output a wired audio signal. The signal processing device is configured
to receive the wired audio signal and to process the wired audio signal
into a first channel signal and a second channel signal. The first
speaker is configured to receive the first channel signal and reproduce
the first channel signal as an audio output. The second earphone includes
a second speaker configured to receive the second channel signal and
reproduce the second channel signal as an audio output. The headset
further includes a transmission means for transmitting the second channel
signal between the signal processing device and the second speaker. Each
of the components of the headset are made of materials having low
magnetic susceptibility.

[0013] According to another aspect of the invention, the transmission
means includes an electrical conductor connected between the first and
second earphones and at least one cable trap connected in series with the
electrical conductor. The cable trap is configured to reduce currents
induced by magnetic fields during an MRI scan. Optionally, the
transmission means includes an optical transceiver in the first earphone,
an optical transceiver in the second earphone, and an optical fiber
connecting the optical transceiver to the optical transceiver. As still
another option, the transmission means includes a second wireless audio
module in the second earphone, and the wireless audio module in the first
earphone is configured to retransmit the second channel signal to the
second wireless audio module.

[0014] These and other objects, advantages, and features of the invention
will become apparent to those skilled in the art from the detailed
description and the accompanying drawings. It should be understood,
however, that the detailed description and accompanying drawings, while
indicating preferred embodiments of the present invention, are given by
way of illustration and, not of limitation. Many changes and
modifications may be made within the scope of the present invention
without departing from the spirit thereof, and the invention includes all
such modifications.

BRIEF DESCRIPTION OF THE DRAWING(S)

[0015] Various exemplary embodiments of the subject matter disclosed
herein are illustrated in the accompanying drawings in which like
reference numerals represent like parts throughout, and in which:

[0016] FIG. 1 is a perspective view of a headset according to one
embodiment of the invention;

[0020]FIG. 5 is a partial exploded view of one of the earphones from the
headset of FIG. 1;

[0021]FIG. 6 is a block diagram representation of the headset according
to one embodiment of the invention;

[0022] FIG. 7 is a perspective view of a headset according to another
embodiment of the invention;

[0023]FIG. 8 is a perspective view of a headset according to another
embodiment of the invention; and

[0024]FIG. 9 is an illustration of an exemplary MRI scan room and control
room.

[0025] In describing the preferred embodiments of the invention which are
illustrated in the drawings, specific terminology will be resorted to for
the sake of clarity. However, it is not intended that the invention be
limited to the specific terms so selected and it is understood that each
specific term includes all technical equivalents which operate in a
similar manner to accomplish a similar purpose. For example, the word
"connected," "attached," or terms similar thereto are often used. They
are not limited to direct connection but include connection through other
elements where such connection is recognized as being equivalent by those
skilled in the art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The various features and advantageous details of the subject matter
disclosed herein are explained more fully with reference to the
non-limiting embodiments described in detail in the following
description.

[0027] Referring initially to FIGS. 1-4, one embodiment of an MRI
compatible headset 10 is illustrated. The headset 10 includes a first
earphone 40 and a second earphone 50. A headband 12 extends between the
first earphone 40 and the second earphone 50. The headband includes a
first end 16 and a second end 18 and includes a curved portion 17
configured to fit a patient's head. Optionally, the length of the
headband 12 may be adjustable to adjust to varying sizes of patient's
heads. The first earphone 40 is mounted to the headband 12 at a first
mounting connection 20 proximate to the first end 16 of the headband 12,
and the second earphone 50 is mounted to the headband 12 at a second
mounting connection 22 proximate to the second end of the headband 12.
Each mounting connection 20, 22 may provide a rigid mount or a pivotal
mount between the earphone 40, 50 and the headband 12. A pivotal mount
allowing each earphone 40, 50 to more comfortably engage the patient's
ear. The headset 10 may also include a foam pad 30 or any other suitable
cushioned material to improve patient comfort. An outer surface 34 of the
foam pad 30 is mounted to an inner surface 14 of the headband 12. The
inner surface 32 of the foam pad 30 is configured to engage the patient's
head.

[0028] Each of the components of the headset are constructed of materials
having low magnetic susceptibility and low magnetic signature. Magnetic
susceptibility is a physical property of materials which identifies to
what degree the material is affected by an applied magnetic field. If a
material has high magnetic susceptibility, it is affected more
significantly by an applied magnetic field, becoming magnetized itself
and being attracted to the source of the applied magnetic field. If the
applied magnetic field is strong enough and the material has a
sufficiently high magnetic susceptibility, an object may be drawn toward
the source of the applied magnetic field. Conversely, materials with, low
magnetic susceptibility are relatively unaffected by an applied magnetic
field. These materials either do not become magnetized or are magnetized
in such a minor degree as they will not be drawn toward the source of the
applied magnetic field. As is understood in the art, MRI scanners
generate magnetic fields having uniform field density and having a field
strength ranging, for example, from 0.5-3 Tesla. As used herein, a
material having low magnetic susceptibility will not be drawn toward the
magnetic field generated by the scanner. A material having a low magnetic
signature will not distort the uniform field to a degree that it would
create an artifact in, an MRI image.

[0029] It is contemplated that the headset 10 may include other
configurations without deviating from the scope of the invention.
According to other embodiments of the invention, each earphone 40, 50 may
include a clip to hook behind a patient's ear to secure the earphone to
the patient. The earphone 40, 50 may a bud-style earphone, configured to
engage a patient's ear canal rather than fit over the ear. Referring also
to FIG. 7, the headset 10 may include a wire 42 extending between the
first earphone 40 and the second earphone 50. The wire 42 may be a
fiber-optic cable, providing a conductive path for photons to be passed
between the two earphones 40, 50. Optionally, the wire 42 may be
electrically conductive and further include one or more cable traps 44
connected in series with the wire 42. The cable trap 44 is configured to
reduce currents induced in the wire 42 from MRI gradients thereby
reducing distortion of the audio signal transferred in the wire 42 and
inductive heating of the wire 42. MRI scanners typically operate at
frequencies in the megahertz, for example, in a range between 60 MHz and
150 MHz. Therefore, the cable traps may be configured to reduce signals
having a similar range of frequencies. Referring also to FIG. 8, the
headset 10 may include a microphone 46 mounted to an arm 48 extending
from either the first end 16 or the second end 18 of the headband 12. The
arm 48 may be movably mounted such that the microphone 46 may be
positioned proximate to the patient's mouth. Optionally, the microphone
46 may be mounted directly to one of the earphones 40, 50. The headset 10
may be realized according to various combinations and arrangements of the
above-described embodiments.

[0030] Referring next to FIG. 5, an exploded view of one of the earphones
40, 50 of FIG. 1 includes a rear housing 52 and a front housing 54. The
front housing 54 includes multiple mounting holes 56 configured to align
with mounting posts 58 in the rear housing 52. A fastener such as a screw
or a bolt is inserted through each mounting hole 56 and engages the
mounting post 58 to positively retain the front housing 54 to the rear
housing 52. The front housing 54 includes a plurality of holes 60 to
facilitate sound waves from a speaker 100 within the housing to travel
through the front housing 54. The speaker 100 is of a low magnetic
susceptibility construction, including, but not limited to a
piezoelectric speaker or an electrostatic speaker. Optionally, the
speaker 100 may include one or more speakers configured, for example, to
reproduce specific frequency bands of an audio signal.

[0031] A cushion 70 is fitted to the front housing 54 and configured to
engage the patient. The cushion 70 includes an opening 72 extending
through the center to facilitate sound waves travelling from the housing
to the patient's ear. An outer periphery 74 of the cushion 70 is greater
than the outer periphery of the housing such that the cushion 70 may fit
over the housing. According to one embodiment of the invention, the
cushion 70 is attached to the housing by a friction fit, allowing the
cushion 70 to be removed and replaced as needed. Optionally, the cushion
70 may be removably mounted to the housing by any other connector, such
as a snap or hook and loop fastener. According to still another
embodiment, the cushion 70 may be secured to the housing, for example, by
an adhesive. The earphone 40, 50 may further include a cover 76 secured
between the cushion 70 and the front housing 54. The cover 76 protects
the earphone 40, 50 preventing dust and dirt from entering the holes 60
in the front housing 54 yet is made of a material that allows the
transmission of the sound waves.

[0032] A spacer 80 is configured to fit within the rear housing 52. The
spacer is shaped complementary to the rear housing 52 and includes
passages 82 extending through the spacer 80 configured to, receive the
mounting posts 58. An opening 84 in the center of the spacer 80 includes
an inner periphery 86. A raised portion 88 on the front face of the
spacer 80 is offset from and extends around the inner periphery 86,
defining a seat for a circuit board 90. The circuit board 90 is
configured to engage the seat on the spacer 80 with a portion, of the
electronic components mounted to each side of the circuit board 90. The
electronic components mounted on the side of the circuit board 90
engaging the spacer 80 fit within the opening 84 of the spacer, and the
mounting posts 58 extend thorough the spacer 80 a sufficient distance to
provide space for the electronic components mounted on the other side of
the circuit board 90. The spacer 80 provides mechanical damping to the
circuit board and, speaker such that they resist vibration caused by
acoustic resonance. As discussed below, the MRI scan room 2 is typically
an acoustically noisy environment and, absent the mechanical damping, the
magnitude of the noise could cause the components to resonate or vibrate,
causing yet more noise proximate to the patient's ear.

[0033] The electronic components on the circuit board are configured to
convert a wireless audio signal to an audio output to the patient.
Referring also to FIG. 6, an antenna 92 receives the wireless audio
signal 104 from an external wireless source 102. The wireless audio
signal 104 may be formatted according to any suitable wireless
communication standard, for example, Bluetooth® or IEEE 802.11. The
wireless audio signal 104 is provided to a wireless audio module 94. The
wireless audio module 94 is a single, integrated circuit including
multiple functions, including, but not limited to radio frequency
modulation and demodulation, digital signal processing, other processing,
and storing data in on board or external memory. According to other
embodiments of the invention, the functions of the wireless audio module
94 may be provided by individual processors or included in various
combinations on one or more processors. An amplifier 98 is connected in
series between the wireless audio module 94 and a speaker 100.

[0034] As used herein, a "wireless" signal is a radio frequency (RF)
signal transmitted from an RF transmitter to an RF receiver where the RF
transmitter and/or receiver may be discrete electronic components, a
portion of an RF transceiver, or a portion of another module, which
includes other features, for example processing of the RF signals, and
any required supporting electronic circuitry.

[0035] Other electronic components 96 are illustrated generally on the
circuit board 90 in FIG. 5 with exemplary components illustrated in block
diagram form in FIG. 6. Each earphone 40, 50 may include a battery 110
and a battery monitor circuit 112. The battery monitor circuit 112
measures the voltage or current level on the battery to determine
performance and/or an expected remaining life of the battery. The battery
monitor circuit 112 generates a signal if the voltage or current level
drops below a predetermined threshold to indicate, for example, low
remaining life of the battery and may be provided to wireless audio
module 94 and transmitted to the remote source 102 or be connected to a
light emitting diode (LED) in the switch and LED module 114. Other
switches and LEDs as required by the headset may include, but are not
limited to a power switch, push-to-talk (PTT) switch, audio source
selection switch, and corresponding LEDs indicating status of any of the
afore mentioned switches or other operating conditions of the headset 10.
Similarly, a display unit 116 may be included to provide a visual
indication of the operating status or configuration status of the headset
10. A programming interface 118 allows new programs and/or configurations
to be loaded into the wireless audio module 94 from a remote programming
device. It is further contemplated that the earphone 40, 50 include a
proximity sensor 120 to detect whether the earphone is being worn by a
patient. Each earphone 40, 50 may additionally be configured to provide
active noise cancellation (ANC). A dedicated, processing device 124 along
with a programming interface 126 for the ANC processing device 124 may be
included. A microphone 122 transfers a signal to the ANC processing
device corresponding to the sounds present proximate to the microphone
122.

[0036] The electronic components 96 are arranged on the circuit board 90
to reduce potential side effects detrimental to either the headset 10 or
the MRI scanner. The electronic components 96 are located in close
proximity to other components to which they are electrically connected,
reducing the length of traces or wire runs between the components,
thereby reducing the potential for heating due to currents induced on
those traces or wire runs by the MRI scanner. The electronic components
96 are also arranged to minimize the formation of loops, which are
susceptible to coupling with the magnetic field from the MRI scanner.
Further, the electromagnetic shielding may be included on a portion of or
on the entire circuit board 90 to reduce the interaction between the MRI
scanner and the circuit board 90.

[0037] According to one embodiment of the invention, the headset 10
includes a first earphone 40 and a second earphone 50 having identical
components with different programs stored in memory of each earphone 40,
50. Optionally, the same program may be stored in memory and each
earphone 40, 50 includes a selector such as a jumper switch that, selects
whether the earphone 40, 50 is, for example, a left/right earphone or a
master/follower earphone. According to another embodiment of the
invention, the headset 10 includes a first earphone 40 and a second
earphone 50 having different sets of components. Referring, for example,
to FIGS. 7 and 8, a wire 42 (electrical or optical) may connect the two
earphones 40, 50. One of the earphones 40, 50 may be configured to
receive the wireless audio signal 104 and perform any required processing
with a single wireless audio module 94. The wireless audio module 94
subsequently outputs the appropriate signal for each speaker 100 either
internally to the earphone 40, 50 or via the wire 42 connecting the two
earphones 40, 50. The other of the earphones 40, 50 may include just the
speaker 100, the amplifier 98 and speaker 100, or any other subset of
components according to the desired level of control, provided in the
second earphone 40, 50.

[0038] In operation, the headset 10 receives a wireless audio signal 104
from a remote source 102 and converts it to an audio signal to the
patient. As illustrated in FIG. 6, each of the earphones 40, 50 include
the same components. One of the two earphones 40, 50 operates as a master
device and the other as a follower device in order to synchronize
playback of the audio signal between the two speakers 100. Therefore, for
purposes of illustration, the first earphone 40 will be referred to as
the master and the second earphone 50 will be referred to as the
follower.

[0039] The antenna 92 in the master earphone 40 receives the wireless
audio signal 104 and transfers it to its respective wireless audio module
94. The wireless audio module 94 is configured to execute a program, or
series of instructions, stored in memory. The wireless audio module 94
processes the wireless audio signal 104 to determine which portion 106
needs to be output from the speaker 100 in the follower earphone 50. This
portion 106 of the wireless audio signal 104 may be the entire signal,
for example, if a single channel signal is received, or one channel of
the signal, if a dual channel signal is received. The master wireless
audio module 94 then transmits this portion 106 of the wireless audio
signal 104 to the follower wireless audio module 94 via the respective
antennas 92. Each of the master and follower wireless audio modules 94
subsequently processes the respective signal 104, 106 received at that
module 94 to provide an output signal 95 from the wireless audio module
94. This output signal 95 is subsequently converted by the respective
amplifier 98 and speaker 100 to an audio signal to the patient.

[0040] The headset 10 is powered by at least one battery 110 having low
magnetic susceptibility. Optionally, each earphone 40, 50 may include a
separate battery 110. The battery 110 may be rechargeable, or
non-rechargeable. For either option, a battery monitor 112 circuit
provides an indication of the level of charge remaining in the battery.
As the energy stored in the battery is used by the headset 10, the
voltage level will decrease. When the voltage level drops below a
predetermined threshold, the headset 10 provides an indication that the
energy level in the battery is low. If the batteries 110 are
rechargeable, either the entire headset 10 or the batteries 110, removed
from the headset, may be placed in a charger to recharge the batteries
110. If the batteries 110 are not rechargeable, they may be replaced.

[0041] A proximity sensor 120 may be used to extend the life of the
batteries. The proximity sensor 120 is operatively mounted on the
earphone 40, 50 to detect when the headset 10 is on a patient's head. The
proximity sensor 120 generates a signal indicating that an object (e.g.
the patient) is near the earphone 40, 50. The wireless audio module 94 is
configurable to operate in a first operating mode or a second operating
mode as a function of the signal generated by the proximity sensor 120.
In the first operating mode, corresponding to the presence of an object
near the proximity sensor 120, the wireless audio module 94 is fully
operational. In the second operating mode, corresponding to the absence
of an object near the proximity sensor 120, the wireless audio module 94
enters a stand-by state, reducing the overall power consumption of the
earphone 40, 50. Optionally, the wireless audio module 94 may remain in
the fully operational state for a predetermined time after the signal
from the proximity sensor 120 is removed.

[0042] The MRI scan room 2 is typically an acoustically noisy environment
due to the operation of the MRI scanner. The noise level may be of
sufficient magnitude to cause discomfort to the patient while obtaining
an MRI image. According to one embodiment of the invention, the inner
periphery 72 of the cushion 70 on each earphone 40, 50 is configured to
surround a patient's ear canal. The cushion 70, therefore, acts as a
passive noise attenuation device, reducing the level of the noise
reaching the patient's ear. In addition, each earphone 40, 50 may include
active noise cancellation. The active noise cancellation may be included
within the wireless audio module 94 or a separate processing device 124
may be included. If a microphone 46 is included for patient
communication, that microphone 46 may be sampled to receive signals
corresponding to the noise, or audio signals, present in the MRI scan
room 2. Optionally, one, or more separate microphones 122 may be mounted
on the earphone 40, 50 and sampled to receive signals corresponding to
the noise, or audio signals, present in the MRI scan room 2. The active
noise cancellation module continually monitors the audible signals to
determine ambient noise and generates a signal in opposition to the
ambient noise. The signal may be, for example, an electronic signal 180
degrees out of phase with the electronic signal representing the ambient
noise. The active noise cancellation module then generates an audible
signal corresponding to the electronic signal which cancels at least a
portion of the ambient noise present in the scan room 2.

[0043] The active noise cancellation may be used either to pro ride
comfort to the patient or to facilitate communication with the patient.
Patient comfort may be increased by measuring the ambient noise and
generating a noise cancelling signal to be reproduced by the speaker 100
of the earphone 40, 50. This signal reduces the level of noise detected
by the patient. Communication with the patient is improved by measuring
the ambient noise and generating a noise cancelling signal which is added
to an audio signal corresponding to the patient's voice. This reduces the
level of ambient noise wirelessly transmitted, for example, to the
operator in the control room 3 during a scan, making it easier for the
operator to understand a patient's response or request.

[0044] It should be understood that the invention is not limited in its
application to the details of construction and arrangements of the
components set forth herein. The invention is capable of other
embodiments and of being practiced or carried out in various ways.
Variations and modifications of the foregoing are within the scope of the
present invention. It also being understood that the invention disclosed
and defined herein extends to all alternative combinations of two or more
of the individual features mentioned or evident from the text and/or
drawings. All of these different combinations constitute various
alternative aspects of the present invention. The embodiments described
herein explain the best modes known for practicing the invention and will
enable others skilled in the art to utilize the invention.